All 6 Uses of

renaissance
in
Atlas Shrugged

The Second Renaissance-not of oil paintings and cathedrals-but of oil derricks, power plants, and motors made of Rearden Metal.
Chpt 1.8

Renaissance = referencing, as the first renaissance, a period of European history known for a revival of intellectual and artistic achievement (14th through mid-17th centuries)

Ellis Wyatt, who had wanted to tap an unlimited source of shale oil and who spoke of a Second Renaissance...
Chpt 1.10 *

There were no superfluous objects, but she noticed a small canvas by a great master of the Renaissance, worth a fortune, she noticed an Oriental rug of a texture and color that belonged under glass in a museum.
Chpt 3.1

Renaissance = a period of European history known for a revival of intellectual and artistic achievement (14th through mid-17th centuries)

Uses with a meaning too rare to warrant foucs:

This is the capital of the Renaissance.
Chpt 1.8

renaissance = a period named in this novel that is based upon the common noun and refers to a notable renaissance in the way that the European Renaissance was notable

I'm going to expand the mills-and if she can give me three-day freight service to Colorado, I'll give you a race for who's going to be the capital of the Renaissance!
Chpt 1.8 *

renaissance = the name of a town in this novel

Definitions:

(1) (renaissance as in: a renaissance)
a revival or renewed interest in something
(2) (Renaissance as in: The Renaissance)
the period of European history known for a revival of intellectual and artistic achievement (14th through mid-17th centuries)

Named as an indication of a rebirth of certain classical ideas that had long been lost to Europe. It has been argued that the movement was strongly influenced by the rediscovery of ancient texts that had been forgotten by Western civilization, but were preserved in some monastic libraries and in the Islamic world, and the translations of Greek and Arabic texts into Latin.

Some historians have suggested that the term Renaissance is loaded and are suggesting the term Early Modern to replace it -- as Middle Ages has largely replaced Dark Ages for the period that preceded the Renaissance.
(3) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

Less commonly, Renaissance can be used as part of a proper noun referring to a period of revival or renewed interest other than the European Renaissance.